Ignition means for a cooking apparatus or the like



Dec. 1, 1970 A. 1.. GOOD 3,544,819

I IGNITION MEANS FOR A COOKING APPARATUS OR TI- IE LIKE I Filed July 19,1968 2 Sheets-Sheet 1 I IO II INVENTOR. ARTHUR L. 6000 HlS ATTORNEYS IY1 FI,G.2 F|G.3 v i wn I Dec. 1, 1970 5000 3,544,819

' IGNITION MEANS FOR A COOKING APPARATUS OR THE LIKE Filed July 19, 1968I 2 Sheets-Sheet 2 INVENTOR. ARTHUR L. GOOD HIS ATTORNEYS United StatesPatent Oflice 3,544,819 Patented Dec. 1, 1970 3,544,819 IGNITION MEANSFOR A COOKING APPARATUS OR THE LIKE Arthur L. Good, Elkhart, Ind.,assignor to Robertshaw Controls Company, Richmond, Va., a corporation ofDelaware Filed July 19, 1968, Ser. No. 746,049 Int. Cl. H01v 7/00 US.Cl. 3108.7 12 Claims ABSTRACT OF THE DISCLOSURE This disclosure relatesto an improved means for altering the stresses in piezoelectric crystalmeans for spark igniting purposes and the like, the stresses in thecrystal means being altered by an electromagnetic motor means having itsarmature balanced between the force of a spring means and thecompressive force of the crystal means being operatively interconnectedto one end of the armature by a lever means pivotally mounted betweenthe ends thereof.

This invention relates to improved apparatus for altering the stressesin a piezoelectric crystal means to cause sparking for ignition purposesor the like.

It is well known that piezoelectric crystal means can have the internalstresses therein altered in a manner to produce an electrical potentialat an electrode interconnected to such crystal means whereby when themagnitude of the potential differential between that electrode andanother electrode reaches a predetermined point, sparking is createdacross the spark gap between such electrodes and such sparking can beutilized to ignite the gaseous fuel and the like issuing from a burnermeans disposed closely adjacent the spark gap.

Therefore, it is a feature of this invention to provide improved meansfor altering the stresses of such a crystal means.

In particular, the illustrated embodiment of this invention has anelectromagnetic motor means operatively interconnected to thepiezoelectric crystal means to alter the stresses therein, theelectromagnetic motor including a movable armature having one enddisposed against one end of a lever pivotally mounted to frame meanscarrying the crystal means in such a manner that the other end of thelever bears against one end means of the crystal means. A spring meansis carried by the frame means and bears against the other end of thearmature so that the spring means always maintains a preload on thecrystal means which has the stresses therein altered by the subsequentenergizing of the coil means of the motor means to cause reciprocatingmovement of the armature.

Accordingly, it is an object of this invention to provide an improvedignition means having one or more of the novel features set forth aboveor hereinafter shown or described.

Other objects, uses and advantages of this invention are apparent from areading of this description which proceeds with reference to theaccompanying drawings forming a part thereof and wherein:

FIG. 1 is a schematic view, partially in cross-section, illustrating theignition means of this invention.

FIG. 2 is a left-hand end view of the actuator of FIG. 1.

FIG. 3 is a right-hand end view of the actuator of FIG. 1.

FIG. 4 is an exploded perspective view of various parts of the actuatorof FIG. 1.

While the various features of this invention are hereinafter describedand illustrated as being particularly adapted to provide sparking forigniting burner means or the like, it is to be understood that thevarious features of this invention can be utilized singly or in anycombination thereof to provide means for altering the stresses inpiezoelectric crystal means for any desired purpose.

Therefore, this invention is not to be limited to only the embodimentillustrated in the drawings, because the drawings are merely utilized toillustrate one of the wide variety of uses of this invention.

Referring now to FIG. 1, the improved ignition means of this inventionis generally indicated by the reference numeral 10 and comprises asupport frame 11 carrying a piezoelectric crystal means or stack,generally indicated by the reference numeral 12, disposed within acutout or slot 13 formed therein and utilized for creating an electricalpotential at an electrode 14 that is spaced from a grounded pilot burnermeans 15 that defines a spark gap 16 therewith. In this manner, thestresses in the piezoelectric crystal means 17 of the crystal stack 12can be altered in a manner hereinafter described and when the potentialdifference between the electrodes 14 and 15 reaches a certain magnitude,electrical sparking is created across the spark gap 16 to ignite fuelissuing from an outlet means 18 of the pilot burner means 15, theignited pilot burner means 15 now being adapted to ignite fuel issuingfrom a main burner means 19 of the cooking apparatus or the likedisposed adjacent thereto.

The crystal stack 12 comprises a cylindrical member 20 having opposedopen ends 21 and 22 and carrying the piezoelectric crystal means 17therein. A pair of pressure pads 23 and 24 are respectively received inthe opposed open ends 21 and 22 of the cylindrical member 20 torespectively engage the opposed ends 25 and 26 of the crystal means 17to help support the crystal means 17 within the cylinder member 20.

As illustrated in FIG. 4, the cutout 13 in the frame 11 defines opposedarcuate surfaces 27 and 28 which are respectively received in annularrecesses 29 and 30 formed respectively in roller means 31 and 32 thatare respectively engaged by the pressure pads 23 and 24 as illustratedin FIG. 1. In this manner, the elements 31, 23, 17, 24 and 32 aredisposed in stacked aligned relation between the opposed arcuatesurfaces 27 and 28 of the frame 11.

A movable member or lever means 33 is pivotally carried by the framemeans 11, the movable member or lever means 33 comprising two like parts34 and 34 fastened together in spaced relation by rivetlike means 35,FIG. 2, so as to operate in unison.

The lever means 33 is pivotally mounted to the frame means 11 by a pivotpin 36 disposed intermediate the opposed ends 37 and 38 of the levermeans 33, the end 37 of the lever means 33 having an arcuate surface 39engaging against the roller means 31 as illustrated in FIG. 1. The otherend 38 of the lever means 33 is disposed in abutting relation and endmeans 40 of a movable armature 41 of an electromagnetic motor 42suitably carried by the frame means 11 in any suitable manner.

The motor means 42 can comprise a conventional AC electromagnetic coilmeans 43 with the shading rings removed and telescopically receiving themovable arma ture 41 therethrough whereby the previously described endmeans 40 of the armature 41 projects to the left beyond the coil means43 and the other end 44 of the armature 41 projects to the right out ofthe core means 43 and has shoulder means 45 for limiting movement of thearmature 44 to the left in 'FIG. 1 when the coil 43 is energized as theshoulder means 45 will abut against the coil support 46.

The frame 11 has a tongue portion 47 projecting to the right thereof inFIG. 1 with a reversely turned tang 48 at the upper end thereof.

A leaf-like spring 49 is best illustrated in FIG. 4 and has an elongatedslot 50 passing therethrough intermediate opposed bowed ends 51 and 52thereof. The slot 50 of the spring 49 permits the spring 49 to beassembled on the tongue portion 47 of the frame 11 in a telescopingmanner as illustrated in FIG. 1 and then be moved vertically downwardlyso that the tang 48 bears against a nonslotted portion of the leafspring 49 as illustrated in FIG. 3. When the spring 49 is assembled inthis manner, the lower end 52 thereof bears against the right-hand end44 of the armature 41 and the upper end 51 of the spring 49 bearsagainst a permanently deformable part 53 of the frame 11 as illustratedin FIG. 1.

In this manner, the deformable part 53 can be permanently deformedrelative to the remainder of the frame 11 so as to provide the desireddegree of bowness of the leaf spring 49 about the abutment or tang 48 ofthe frame 11 so that the spring 49 will tend to move the armature 44- tothe left in FIG. 1 with a predetermined force resisted only by thecrystal means 17 that is, thus, being compressed by the lever or movablemember 33 tending to be moved in a clockwise direction by the spring 49.

Therefore, it can be seen that in the position of FIG. 1, the armature44 is balanced between the force of the leaf spring 49 tending to movethe same to the left in FIG. 1 and the resisting compression force ofthe crystal means 17 tending to pivot the lever 33 in a counterclockwisedirection. Accordingly, the crystal means 17 not only always has apreloading force thereon provided by the spring means 49', but also suchpreloading force maintains the elements 31, 23, 17, 24 and 32 in stackedcompressed relation.

From the above, it can be seen that the ignition means of this inventioncan be formed of a relatively few parts that can be manufactured andassembled together in a relatively simple manner to be utilized forignition purposes in a manner now to be described.

When the housewife or the like desires to turn on the main burner means19 of the cooking apparatus by operating the respective selector knobtherefor (not shown) and the burner means 19 does not ignite because ofthe pilot burner means being unlit, or when she actually notices thatthe pilot burner means 15 has been extinguished for some reason, thehousewife or the like can effect the ignition of the pilot burner means15 by causing the electromagnetic motor means 42 to repetitively pivotthe movable member lever means 33 first in a clockwise direction in FIG.1 and then backwards in a counterclockwise direction one or more timesas desired or as automatically determined by suitable timer means.

In particular, the housewife or the like, when energizing the coil 43 ofthe electromagnetic motor means 42 either by manually completing anelectrical circuit thereto or by causing an automatic timer means tocomplete the electric circuit thereto for a predetermined period of timeafter the lapse of which the timer means will terminate the electricalcurrent to the coil means 43, causes the armature 41 to reciprocaterelative to the coil 43 in a manner well known in the art as long as thecoil is electrically interconnected to an alternating current.

In any event, the armature 41 is initially moved or drawn to the left inFIG. 1 by one cycle of the energized coil means 43 to cause the levermeans 33 to pivot in a clockwise direction whereby the arcuate surface39 on the end 37 of the lever means 33 acts against the roller means 31to longitudinally compress the crystal means 17 between the pressurepads 23 and 24 to alter the stresses therein in such a manner that theresulting potential now being created at the electrode 14 will cause adischarge across the spark gap 16 in cooperation with the grounded pilotburner means 15 one or more times during such clockwise movement of thelever means 33 whereby such sparking at the spark gap 16 will ignitefuel issuing from the outlet 18 of the pilot burner means 15.

Conversely, when the next cycle of the coil means 43 ceases to pull orhold the armature 44 to the left in FIG. 1, the armature 44 is permittedto move back to the right by the force of the previously squeezed orcompressed crystal means 17 which is now permitted to longitudinallyexpand and cause the lever means 33 to move back in a counterclockwisedirection in opposition to the force of the leaf spring 49 whereby thethus expanding crystal means 17 is also having its stresses altered sothat the resulting potential difference between the electrodes 14 and 15will also cause sparking at the spark gap 16 one or more times tosubstantially assure that the pilot burner means 15 will be ignited.

Accordingly, it can be seen that the electromagnetic motor means 42 ofthis invention is utilized to effect reciprocating movement of thearmature 41 and, thus, repetitive clockwise and counterclockwisemovement of the lever means 43 to alternately and repetitively provide asqueezing action on the crystal means 17 and then a relieving of suchsqueezing action on the crystal means 17 to alter the stresses thereinfor the aforementioned ignition purposes as long as the coil 43 is beingenergized by an alternating current.

While the ignition means 10 of this invention has been previouslydescribed as being utilized in connection with a cooking apparatus, itcan be seen that the ignition means 10 of this invention provides anelectromechanical means of actuating the piezoelectric crystal means 17in order to produce a high electrical potential resulting inintermittent sparking of high frequency across the spark gap 16 wherebysuch sparking could be considered for use in oil burner ignition systemsor with any other types of volatile fuel.

Therefore, this invention not only provides an improved piezoelectriccrystal actuator means, but also this invention provides improvedignition means for a burner or the like.

What is claimed is:

1. In combination, frame means, piezoelectric crystal means carried bysaid frame means, a movable member carried by said frame means and beingoperatively inter connected to said crystal means to alter the stressestherein when said member is moved in a particular direction,electromagnetic motor means carried by said frame means and beingoperatively interconnected to said movable member to move the same whensaid motor means is energized, said movable member being pivotallymounted to said frame means between opposed end means of said member,one end means of said member bearing against an adjacent end means ofsaid crystal means and the other end means of said member bearingagainst said motor means, and spring means carried by said frame meansand being operatively interconnected to said motor means to tend tomaintain a constant load on said crystal means through said movablemember.

2. A combination as set forth in claim 1 wherein said motor means has amovable armature provided with opposed end means, one of said end meansof said armature being disposed against said other end means of saidmovable member and the other end means of said armature being engaged bysaid spring means whereby said spring means tends to move said armaturein a direction to preload said crystal means.

3. A combination as set forth in claim 2 wherein said motor means has anelectrical coil means, said armature passing through said coil meanswith said opposed end means thereof extending beyond the opposed endmeans of said coil means.

4. A combination as set forth in claim 5 wherein said spring meanscomprises a leaf spring that is carried by said frame means and hasopposed ends, one of said ends engaging said other end means of saidarmature to tend to preload said crystal means with a compressive force.

5. A combination as set forth in claim 4 wherein said frame means has atongue portion, said leaf spring having a slot passing therethroughbetween said opposed ends thereof and receiving said tongue portion,said tongue portion having an abutment engaging against said springbetween said slot and the other end thereof, said other end of saidspring abutting said frame means whereby said spring is bowed betweensaid ends thereof by said abutment.

6. A combination as set forth in claim 5 wherein said frame means has adeformable part that is engaged by said other end of said spring topermanently adjust the bow of said spring in relation to the deformingof said part relative to said frame means.

7. In combination, a burner means for issuing fuel, electrode meansassociated with 'said burner means for creating electrical sparking toignite said issuing fuel, frame means, piezoelectric crystal meanscarried by said frame means, means electrically interconnecting saidcrystal means to said electrode means, a movable member carried by saidframe means and being operatively interconnected to said crystal meansto alter the stresses therein and create said electrical sparking atsaid electrode means when said member is moved in a particulardirection, electromagnetic motor means carried by said frame means andbeing operatively interconnected to said movable member to move the samewhen said motor means is energized, said movable member being pivotallymounted to said frame means between opposed end means of said member,one end means of said member bearing against an adjacent end means ofsaid crystal means and the other end means of said member bearingagainst said motor means, and spring means carried by said frame meansand being operatively interconnected to said motor means to tend tomaintain a constant load on said crystal means through said movablemember.

8. A combination as set forth in claim 7 wherein said motor means has amovable armature provided with opposed end means, one of said end meansof said armature being disposed against said other end means of saidmovable member and the other end means of said armature being engaged bysaid spring means whereby said spring means tends to move said armaturein a direction to preload said crystal means.

9. A combination as set forth in claim 8 wherein said motor means has anelectrical coil means, said armature passing through said coil meanswith said opposed end means thereof extending beyond the opposed endmeans of said coil means.

10. A combination as set forth in claim 15 wherein said spring meanscomprises a leaf spring that is carried by said frame means and hasopposed ends, one of said ends engaging said other end means of saidarmature to tend to preload said crystal means with a compressive force.

11. A combination as set forth in claim 10 wherein said frame means hasa tongue portion, said leaf spring having a slot passing therethroughbetween said opposed ends thereof and receiving said tongue portion,said tongue portion having an abutment engaging against said springbetween said slot and the other end thereof, said other end of saidspring abutting said frame means whereby said spring is bowed betweensaid ends thereof by said abutment.

12. A combination as set forth in claim 11 wherein said frame means hasa deformable part that is engaged by said other end of said spring topermanently adjust the bow of said spring in relation to the deformingof said part relative to said frame means.

References Cited UNITED STATES PATENTS 3,211,949 10/1965 Slaymaker etal. 3108.3X 3,389,275 6/1968 Brothers 310-83 3,444,435 5/1969 Halm310-81 3,462,234 8/1969 Branson et al. 431--255 FOREIGN PATENTS1,099,969 1/1968 England 310-83 MILTON O. HIRSHFIELD, Primary ExaminerM. O. BUDD, Assistant Examiner US. Cl. X.R.

